Incidental light readings not possible anymore??

[I Simonius]

I used to be able to take an 'incident' light reading with film by putting a white plastic cover over the lens facing the light falling on the subject and taking a reading.

I tried this with the DSLR and it doesn't work

Can anyone tell me why??


(I wasn't sure which thread to post this so I'mexpecting it to be moved.....)

[David1943]

Sounds a bit hit and miss to me, as wouldn't the amount of light entering through the lens be regulated by the density of the plastic which would I think need to be designed especially for the camera and lens.

I do recall, however, owning many years ago a Weston Master V light meter which took reflected light readings but which came with a plastic dome called a invercone which could be fitted on to it and thus turn it into an incident light meter. A very accurate way of measuring the light actually falling on to the subject.

Regards, David :)

[I Simonius]

Sounds a bit hit and miss to me, as wouldn't the amount of light entering through the lens be regulated by the density of the plastic which would I think need to be designed especially for the camera and lens.

I do recall, however, owning many years ago a Weston Master V light meter which took reflected light readings but which came with a plastic dome called a invercone which could be fitted on to it and thus turn it into an incident light meter. A very accurate way of measuring the light actually falling on to the subject.

Regards, David :)


Sorry - should have said - not any old piece of plastic - you used to be able to buy them specifically for this purpose

It was essentially an invercone for the camera rather than for the light meter (same thing reallly as the camera has a light meter in it)

BUT -- why doesn't it work on the DSLR?

[hmhm]

Sounds like an expodisc (www.expodisc.com). There's no reason why such a device shouldn't work on a DSLR. What, exactly, did you do, and what, exactly, was the result?

The metering systems on DSLRs aren't, in any fundamental way, different from the metering systems on a film SLR.
-harry

[Jesper]

Sounds like an expodisc (www.expodisc.com). There's no reason why such a device shouldn't work on a DSLR. What, exactly, did you do, and what, exactly, was the result?

The metering systems on DSLRs aren't, in any fundamental way, different from the metering systems on a film SLR.
-harryNo, the ExpoDisc is for white balance, not for exposure metering.

[SeanH]

Just use a gray card.

[I Simonius]

Just use a gray card.

Less discreet than a invercone thingy, and also gray cards are difficult in bright sunlight sometimes due to glare

[hmhm]

No, the ExpoDisc is for white balance, not for exposure metering.
It's both a floor wax and a dessert topping. It was actually originally created back when film roamed the earth. The "hey, this can be used for white balance" idea was an afterthought, it was originally conceived as a tool for exposure metering.
-harry

[RTMiller]

It's both a floor wax and a dessert topping.
That's too funny!!!

[Curtis N]

Sounds like an expodisc (www.expodisc.com (http://www.expodisc.com/)). $99.95 US for this thing? Come on. I like nifty gadgets but that's a little steep.

[Mark_48]

I used to be able to take an 'incident' light reading with film by putting a white plastic cover over the lens facing the light falling on the subject and taking a reading.

I tried this with the DSLR and it doesn't work


How didn't it work? Overexposed, underexposed, or just inconsistant readings.

[I Simonius]

How didn't it work? Overexposed, underexposed, or just inconsistant readings.

The readings were way off

I will post some examples tomorrow if I get the chance

[puttick]

It's not magic - either:

(1) Buy a separate meter (I have a 40 year old Weston Master that does this perfectly)

or

(2) meter off a gray card (place the card so the card is facing the camera position, and so is receiving the same lighting that is falling on the scene)

It is a good way of getting an average exposure for a difficult scene, for example one with a wide brightness range such as bright sun and dark shadows. The idea is to place an 18% gray object on the mid-point of the sensitometric curve (in this case, the middles of th histogram). Of course, that is not always what you want to achieve!

Nigel

[I Simonius]

It's not magic - either:

(1) Buy a separate meter (I have a 40 year old Weston Master that does this perfectly)

or

(2) meter off a gray card (place the card so the card is facing the camera position, and so is receiving the same lighting that is falling on the scene)

It is a good way of getting an average exposure for a difficult scene, for example one with a wide brightness range such as bright sun and dark shadows. The idea is to place an 18% gray object on the mid-point of the sensitometric curve (in this case, the middles of th histogram). Of course, that is not always what you want to achieve!

Nigel

I had a weston - so long ago- I rue the day I let it go.

I do have a grey card but prefer the discretion of an incident meter, whatever the shape

[puttick]

Then all you need to do is find a piece of translucent plastic to fit over your lens, that gives the same reading when viewed through the dSLR finder as you get off your gray card. Start with a Pringles tube lid perhaps?

Another thought - use a spare UV filter coated with vaseline or perhaps a sheet of tissue - keep adding layers until the reading equals that off the gray card?

8^)

PS My Weston Master V is not for sale - I need it for my Leica IIIf

[I Simonius]

Then all you need to do is find a piece of translucent plastic to fit over your lens, that gives the same reading when viewed through the dSLR finder as you get off your gray card. Start with a Pringles tube lid perhaps?

Another thought - use a spare UV filter coated with vaseline or perhaps a sheet of tissue - keep adding layers until the reading equals that off the gray card?

8^)

PS My Weston Master V is not for sale - I need it for my Leica IIIf

Piece of plastic I have - but it don't work..

Leica...
:rolleyes:

[wilflee]

Just curious.. which metering mode are you using? Have you tried the simple center weighted average mode?

I'm guessing the camera's high tech metering computer is trying to be too smart, evaluating different zones etc. and not coming up with a simple reading. Afterall, the metering computer is designed to read reflected light and analyze the scene at multiple points. You may need to "dumb down" the meter.

[chtgrubbs]

$99.95 US for this thing? Come on. I like nifty gadgets but that's a little steep.
Yeah, they were only $17.95 when they came out in the '80s, before someone discovered they were useful for the new and expensive high tech digital cameras! And we thought they were overpriced then!

[I Simonius]

Just curious.. which metering mode are you using? Have you tried the simple center weighted average mode?

I'm guessing the camera's high tech metering computer is trying to be too smart, evaluating different zones etc. and not coming up with a simple reading. Afterall, the metering computer is designed to read reflected light and analyze the scene at multiple points. You may need to "dumb down" the meter.

good point - I'll try with CW average - that might do it!